Microsoft will ship the Xbox One with an internal 500GB hard drive and a USB 3.0 port that will, eventually, allow you to use external storage to manage game downloads and installs.

The feature won't be in the machine at launch, however. "My understanding is that feature will not be there at launch because the team is working on some other things, but it definitely is on the list," said Hryb. "I don't know when it will come in, though."

Elsewhere, Sony Worldwide Studios boss Shuhei Yoshida confirmed that the PlayStation 4 will not allow you to install PS4 games to an external hard drive.

Like the Xbox One, the PlayStation 4 also ships with a 500GB internal hard drive. Sony will allow users to replace the hard drive, however.